A WLAN in infrastructure basic service set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP typically may have access or interface to a distribution system (DS) or another type of wired/wireless network that carries traffic in and out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be transmitted to the AP to be delivered to the respective destinations. Traffic between STAs within the BSS may also be transmitted through the AP where the source STA transmits traffic to the AP and the AP delivers the traffic to the destination STA. Such traffic between STAs within a BSS may be considered to be peer-to-peer traffic. Such peer-to-peer traffic may also be transmitted directly between the source and destination STAs with direct link setup (DLS) using an Institute of Electrical and Electronics Engineers (IEEE) 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN in Independent BSS mode may have no AP, and STAs may communicate directly with each other.
With the proliferation of personal mobile devices and applications such as meters and sensors, it is expected that future Wireless Fidelity (WiFi) systems that operate in accordance with IEEE 802.11 standards, and associated APs, may require support for a much larger number of devices than those currently in operation. The required number of STAs that may need to be supported may be much more than the current limitation of 2,007 devices per BSS. For example, in IEEE 802.11ah, it may be required to support up to 6,000 devices per BSS. Dense STA and AP deployment may also be possible.
New spectrum is being allocated in various countries around the world for wireless communication systems such as WLANs. Channels allocated in this spectrum may often be quite limited in size and bandwidth. In addition, the spectrum may be fragmented in that available channels may not be adjacent, and it may not be possible to combine them to support larger transmission bandwidths. Such may be the case for example in spectrum allocated below 1 GHz in various countries. WLAN systems, for example based on IEEE 802.11, may be designed to operate in such spectrum. Given the limitations of such spectrum, WLAN systems may only be able to support smaller bandwidths and lower data rates compared to high throughput/very high throughput (HT/VHT) WLAN systems, for example, based on IEEE 802.11n/802.11ac.